Directional recrystallization by zone annealing in a Ni-based ODS superalloy

Ukai, Shigeharu; Taya, K.; Nakamura, Kazuyuki; Aghamiri, Mohammad; Oono, Naoko; Hayashi, Shigenari; Okuda, Takanari

doi:10.1016/j.jallcom.2018.01.406

Cited by 31 publications

(17 citation statements)

References 18 publications

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“…Specially, some relatively large grains surrounded by tiny ones are closely related with the (001) and (111) orientation during the initial hot compression. It is widely accepted that these necklace structure of tiny grains are distributed on the original serrated grain boundaries, which are defined as dynamic recrystallized grains . Generally, the process of DRX of Ni‐based superalloys is promoted with the increased temperatures, as displayed in Figure a–c .…”

Section: Resultsmentioning

confidence: 99%

Texture Evolution and Dislocation Behavior in a Nickel‐Based Superalloy during Hot Compression

Gao

Jia

Ji³

et al. 2019

Adv Eng Mater

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Texture evolution and dislocation behavior of Ni‐based superalloys at various temperatures and strain rate of 1 s−1 are studied using electron backscatter diffraction (EBSD) technique and transmission electron microscope (TEM). It can be concluded that no significant texture is formed at high deformation temperature, especially for the occurrence of completed dynamic recrystallization (DRX). In addition, texture weakening is easy to realize by conducting DRX process on the Ni‐based superalloys, whereas a slight strengthening is observed during grain growth. Based on the TEM images, the original grain boundary with high orientation gradient at low temperature provides an excellent position for DRX nuclei, which is strongly related with the dislocation motion. Moreover, it is concluded that the dislocation behavior plays a significant role in the plastic deformation of the Ni‐based superalloys. Herein, theoretical guidance for the application of nickel‐based superalloys and furthermore enhancement of their plastic deformation properties is provided.

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Section: Resultsmentioning

confidence: 99%

Texture Evolution and Dislocation Behavior in a Nickel‐Based Superalloy during Hot Compression

Gao

Jia

Ji³

et al. 2019

Adv Eng Mater

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“…[ 21 ] This processing leads to controlling the grain structure into the large elongated grains with the advantage of high‐temperature performance, as previously performed in single‐phase Ni‐based ODS superalloys. [ 29 ] Figure a,b shows the morphology of γ′ precipitates after zone annealing and then solution annealing and subsequent one‐step aging in low and high magnifications, respectively. It is evident that γ′ remain in the nanoscale lamellar structure with [200] direction during reprecipitation, even after performing the last processing step of zone annealing at a high temperature with the presolutionizing of γ′ precipitates.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of Processing Conditions on the γ′ Morphology of an Oxide Dispersion Strengthened Ni‐Based Superalloy

et al. 2020

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Herein, the evolution of the microstructure of a newly developed oxide dispersion strengthened (ODS) Ni‐based superalloy with emphasis on γ′ morphology during different processing conditions is investigated. X‐ray analysis of severely deformed mechanically alloyed (MAed) powders shows that the as‐milled nano‐sized crystallite size increases with annealing associated with the sharp drop of dislocation density. At the same time, by annealing MAed powders γ′ precipitates above 300 °C, and depending on the aging treatment regime, Vickers microhardness changes mainly due to γ′ distribution and dislocation release. The thorough evaluation of γ′ morphology in the microscale shows that in contrast to the spherical shape of γ′, after heat treatment of solutionized MAed ODS superalloy, irregular‐shaped γ′ exist in the MAed ODS superalloy due to severe plastic deformation during mechanical alloying. However, a unique nanostructured lamellar morphology forms in the γ′ precipitates with different lamellae directions. This structure is stable in all subsequent processing steps with γ′ lamellae of (011true¯) planes and intervals of 20–30 nm. The scanning transmission electron microscopy (STEM)–high‐angle annular dark‐field (HAADF) composition analysis clarifies that the nanostructured lamellar morphology shows no partitioning of alloying elements, and its origin may be attributed to the formation of antiphase domain boundaries.

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“…Although there are some reports discussing on the possibility of recrystallization in room temperature in copper alloys from some decades ago, however, the detailed and quantitative discussion on the process of recrystallization at such a low temperature (~0.22 Tm) is still lacking. In order to evaluate the progress of recrystallization, it needs to study the velocity of grain boundary migration (V) as the following equation [23]:…”

Section: Recrystallizationmentioning

confidence: 99%

“…where, M is the grain boundary mobility and ΔGt is the total driving force of grain boundary migration. The grain boundary mobility is considered as the following relation [23]:…”

Section: Recrystallizationmentioning

confidence: 99%

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Microstructure development in cryogenically rolled oxide dispersion strengthened copper

et al. 2020

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Directional recrystallization by zone annealing in a Ni-based ODS superalloy

Cited by 31 publications

References 18 publications

Texture Evolution and Dislocation Behavior in a Nickel‐Based Superalloy during Hot Compression

Texture Evolution and Dislocation Behavior in a Nickel‐Based Superalloy during Hot Compression

Evaluation of Processing Conditions on the γ′ Morphology of an Oxide Dispersion Strengthened Ni‐Based Superalloy

Microstructure development in cryogenically rolled oxide dispersion strengthened copper

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